For the toffee cocoa cookie crumble cake, first prepare the toffee sauce. For this, let the sugar caramelize. When the sugar is brown, add the butter and let it foam up. Pour in the whipped cream and simmer gently over low heat for about 10 minutes.
Finely crumble the cocoa cookies and knead with the butter and flour until coarse crumbles form.
Peel the bananas, core the apples and cut the fruit into small pieces. Season with the applesauce and a few squeezes of lemon juice and mix with the toffee sauce and the egg.
Pour the mixture into an ovenproof dish and spread the cocoa cookie pieces on top. Bake at 160°C top and bottom heat for 25 to 30 minutes.
Sprinkle the toffee cocoa cookie crumble cake with powdered sugar before serving.